East Corridor of the Basilica                          -      N      - 
(-------------------------------------------------)     W <---(M)---> E
                                                        -      S      -

The interior is quite remarkable, well-lit and immense.  Directly in
front of you are three giant barrel-vaulted bays, a main hallway, and
another set of bays.  The aisle that runs north and south is divided by two